I figured out I was gay this year and I love my guy best friend. The only thing is: he's straight and just got into a relationship. I act like I'm happy for him, but in reality I cry whenever I hear about them making out or kissing or just together in general. I just wish I didn't fall for him.

It hurts, I know, but on the bright side it's easier to be able to say 'he's straight so there's no chance and he's in a relationship so there's no chance' than to be stuck feeling like 'do I tell him and risk our friendship or forever wonder?'
You get to know the answer without the risk. It's not the answer you want, but there'll be somewhere out there for you who'll make you glad this guy is straight, I promise.